1. Field of the Invention
The present invention relates to a chip-type electronic component including an external electrode connected to an internal conductor, and more particularly, relates to a chip-type electronic component which has an external electrode including a resin electrode layer containing a conductive constituent and a resin constituent and a plating metal layer covering the resin electrode layer.
2. Description of the Related Art
For example, a laminated ceramic capacitor which is one of typical chip-type electronic components has a structure including a body composed of a ceramic dielectric, a plurality of internal electrodes provided in the body, and an external electrode provided for electrical conduction to the plurality of internal electrodes.
Furthermore, this laminated ceramic capacitor (chip-type electronic component) is required to have an excellent effect of relaxation of stress due to a deflection of a substrate with the chip-type electronic component mounted thereon, make it less likely to degrade the electrical properties and cause cracks with higher reliability, as compared with conventional chip-type electronic components, even when the substrate is subjected to deflection stress.
Then, as a chip-type electronic component which meets the requirements, a chip-type electronic component including external electrodes on end surfaces of a chip-shaped body composed of a ceramic sintered body has been proposed in which the external electrodes each have a first electrode layer formed by sintering a conductive paste and a second electrode layer composed of a conductive resin provided to cover the first electrode, the first electrode layer and the second electrode layer are formed to wrap around the side surfaces adjacent to the end surface from the end surface of the chip-shaped body, and the wrapping around length of the first electrode layer is not more than 0.7 times the wrapping around length of the second electrode layer (see Japanese Patent Application Laid-Open No. H10-284343).
In addition, a laminated ceramic capacitor has been proposed in which an external electrode composed of, from a porcelain body side, a first conductor layer containing a glass constituent, a second conductor layer containing a resin constituent, and a third conductor layer composed of a plating metal is formed on both end surfaces of the porcelain body composed of dielectric layers and internal electrode layers stacked alternately, and when the connection strength between the porcelain body and the first conductor layer and the connection strength between the first conductor layer and the second conductor layer are respectively designated by F1 and F2, F1 and F2 satisfy the following requirements (see Japanese Patent Application Laid-Open No. H11-219849):
F1≧1.0 kgf;
F2≧1.0 kgf; and
F1>F2
However, when the chip-type electronic component from Japanese Patent Application Laid-Open No. H10-284343 is mounted onto a substrate to carry out a substrate bending test, deflection stress is concentrated on ends of the first electrode layer formed by sintering a conductive paste or of the second electrode layer composed of a conductive resin formed thereon to cause the ceramic body to be cracked from the ends, leading to a problem of defective short-circuit in some cases. Thus, the reality is that the reliability is not necessarily sufficient.
In addition, when a chip-type electronic component which has the structure as described in Japanese Patent Application Laid-Open No. H11-219849 is mounted on a substrate to carry out a substrate bending test, fracturing is caused between the first conductor layer containing a glass constituent and the second conductor layer containing a resin constituent, where the connection strength is lower than that between the porcelain body and the first conductor, to make moisture more likely to infiltrate into the porcelain body (ceramic body), thereby resulting in a problem of decreased reliability.